Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
Chemphyschem. 2013 May 10;14(7):1451-5. doi: 10.1002/cphc.201201045. Epub 2013 Mar 20.
We compare the time- and angle-dependent strong-field ionization yields of three molecules with very similar electronic structure. A pump pulse in the deep ultraviolet excites 1,3-cyclohexadiene, α-terpinene, and α-phellandrene to their first excited state. The latter two molecules are alkyl-substituted 1,3-cyclohexadiene systems. We then measure the strong-field ionization yield due to a near infrared probe pulse as a function of delay and angle between pump and probe polarization vectors. Ab initio electronic structure calculations allow us to associate the parent ion yields with removal of an electron from a LUMO orbital (occupied after excitation by the pump). Despite the fact that the LUMO orbitals for these molecules are very similar, the angle-dependent yields are very different, indicating that it is not the orbital shape alone which determines angle-dependent ionization yields.
我们比较了三种分子的时间和角度依赖性强场电离产率，这三种分子具有非常相似的电子结构。深紫外光的泵浦脉冲将 1,3-环己二烯、α-萜品烯和α-水芹烯激发到它们的第一激发态。后两种分子是烷基取代的 1,3-环己二烯体系。然后，我们测量了由于近红外探测脉冲引起的强场电离产率作为泵浦和探测偏振向量之间的延迟和角度的函数。从头算电子结构计算使我们能够将母体离子产率与从 LUMO 轨道（在泵浦激发后被占据）中去除一个电子相关联。尽管这些分子的 LUMO 轨道非常相似，但角度相关的产率却非常不同，这表明决定角度相关的电离产率的不仅仅是轨道形状。
